The Radio Record AC/DD4A is an indirectly heated double diode designed for low current signal applications as the maximum anode current is 0.8 mA. Thrower gives details but in the book gives the valve a top cap for one anode. In fact the base connections match the DD4.The entry in RVD-082 has been corrected by the museum.
The reverse is plain zinc paint but carries the overprint of the word Foreign to denote an imported valve.The classic envelope is 28 mm in diameter and, excluding the B5 base pins, is 79 mm tall. |
Pin Connections
| 1 | 2 | 3 | 4 | 5 |  a(1) | a(2) | h | h | k |
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Absolute Maximum Operating Conditions¶
| Vh | Ah | Va | mAa |
| 4.0 | 0.65 | 200 | 0.8 |
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Updated July 12, 2023.
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